In food packaging processes, packaged food products may be sent through a thermal processing tunnel (e.g., pasteurization/microwave tunnel or the like). Shielding and parasitic antennas can be disposed within a package to cause some food components to be affected less or more by applied microwave radiation in the tunnel than other food components within the package. Yet, even with shielding and antenna configurations, it remains a challenge to properly pasteurize or cook certain packaged food products without undercooking or overcooking neighboring food components within the package.